1. Field
Embodiments of the present invention relate to a display device and a driving method of the same.
2. Description of the Related Art
Display devices are needed for the widely used devices of today, such as computer monitors, televisions, mobile phones, or the like. Display devices that display images using digital data include, for example, cathode-ray tube display devices, liquid crystal display (LCD) devices, plasma display panels (PDP), organic light emitting diode (OLED) display devices, or the like. The speeds of data transfer of these display devices are increasing as they become higher resolution and larger.
Meanwhile, one of the factors that contribute to improvement in display quality of an OLED display device may be gamma setting. Gamma setting is a correlation between display luminance and grayscale data, which may be defined by a gamma curve. Generally, display devices have a gamma characteristic such that the luminance of an image displayed does not increase linearly with an input signal level applied to a pixel. Here, gamma correction refers to adjustment due to the photoelectric conversion characteristics of the camera and the television being different and nonlinear (e.g., when light is converted into electric signals in a camera, and when a reverse process of converting the converted electrical signals back to image is performed in a television). A mathematical expression applicable here may be demonstrated as a curve, which is called a gamma curve.
Accurate gamma setting allows an OLED display device to maintain stable display quality. However, when there is an error in gamma setting, there may be difference between real display luminance and the luminance corresponding to grayscale data. To correct this difference, a reference gamma voltage, which is a voltage input into a driving circuit that generates data signals that determine display luminance, may be programmed in real time. In accordance with grayscale data, the driving circuit may use the reference gamma voltage to generate data signals, and light emitting diodes may emit light in accordance with the data signals. Therefore, when the reference gamma voltage is changed, the display luminance of the OLED display device is changed.